A headphone of an over-ear type, for example, is worn on the head of a user who listens to a musical sound from a sound source such as a music player. The headphone has a pair of sound emission units (ear pieces) and a connection member connecting the sound emission units.
Each sound emission unit includes a driver unit, a baffle plate, an acoustic resistor, and a housing. The driver unit converts electric signals (audio signals) from a sound source, such as a music player, to sound waves and outputs the sound waves. The driver unit includes a diaphragm, a magnetic circuit, and a unit case. The driver unit is of a dynamic type. The unit case is composed of synthetic resin which does not interfere with the magnetism of the magnetic circuit.
The driver unit is held by the baffle plate and accommodated in the housing. The acoustic resistor is disposed in the rear side (the side opposite to the side in which the driver unit outputs sound waves) of the driver unit.
Recently, a typical headphone includes sound emission units rotatable relative to the connection member or foldable toward the connection member so as to allow a compact storage of the headphone into a bag, for example. However, such a typical headphone receives strong shock inside the bag when the bag with the headphone accommodated therein collides with an object. When the headphone receives strong shock, the driver unit may be detached from the baffle plate, and the headphone may be broken down. Thus, the driver unit east be securely fixed to the baffle plate.
Various schemes have been proposed to fix the driver unit to the baffle plate: For example, the driver unit is fixed to the baffle plate with an adhesive (for example, refer to Japanese Unexamined Patent Publication No. 2014-127730); the driver unit is fitted into the peripheral wall provided on the baffle plate (for example, refer to Japanese Unexamined Patent Publication No. 2011-87048); the driver unit is fixed with claw members standing on the baffle plate (for example, refer to Japanese Unexamined Utility Model Application Publication No. 1993-80090); and the driver unit is fixed with a cylindrical fixing member (for example, refer to Japanese Unexamined Patent Publication No. 2016-100647).